A communication system typically operates in accordance with a given standard or specification which sets out what the various elements of the system are permitted to do and how that should be achieved. For example, the standard or specification may define if the user, or more precisely, a user equipment or terminal is provided with a circuit switched service or a packet switched service or both. The specification may also define the communication channels through which the signalling associated with various communication tasks are to be communicated. The manner how communication shall be implemented between the user equipment and the elements of the communication network may be based on a predefined communication protocol. In other words, a specific set of “rules” on which the communication can be based on needs to be defined to enable communication by means of the communication system.
In order be able to operate in a predefined manner, various different functions needs to be provided in a communication system. These functions can be divided in different categories. A category comprises functions that relate to the actual transportation of communication such as communication of voice, text or multimedia or other data. Another category can be seen as being formed by control or management functions. These include the control of the communication of voice, text, multimedia and other data communication. Provisioning of various services for the users needs also be controlled by appropriate control functions.
Signalling of messages associated with different functions is understood as being implemented on different planes. For example, control messages are communicated on a control plane and the actual communication of voice, data and so on is transported on a user plane. The communication on the user plane can be supported by the signalling of the control messages on the control plane. The skilled person in the art of communication systems is familiar with principles of dividing various functions into planes, and therefore these will not be explained in any greater herein.
Typically the communication systems provide this by means of separate channels, e.g. by means of separated signalling and communication channels. Such arrangements are employed e.g. by signalling system 7 (SS7) core networks and Q.931/GSM/WCDMA (Global system for Mobile communication/Wideband Code Division Multiple Access) subscriber access. Therefore the term “Signalling channel” may sometimes be used when referring to control plane communications. Similarly the term communication channel may be used when referring to user plane communications.
The various functions of the communication systems may have been developed quite independently from each other and may use different rules such as protocols in different communication systems. The standards and protocols define e.g. which plane shall be used for a certain purpose.
Various services can be provided for a user of a user equipment by means of a communication system. The services can be provided by the operator or operators of the communication system, such as a telephone or data network operator. At least a part of the services can be provided by service providers that are external and/or independent from the operators of the communication system.
Communication network systems that provide mobility for the users thereof are known. The skilled person is aware of the basic principles of such mobile communication systems. A well known example is the public land line mobile network (PLMN), known also as a cellular communication network. Another example is a mobile communication system that is at least partially based on use of communication satellites.
Services that utilise information ab1out the geographical location of a mobile user equipment (and thus the user) in the service provisioning are also known. Such services are sometimes referred to as location sensitive services. Recent development in the field of mobile communications has lead to arrangements wherein information about the current location of a mobile user equipment is determined and can be utilised in provision of various services for the user of the mobile user equipment.
The mobile network apparatus and/or mobile user equipment such as a mobile station can be employed for provision of information regarding the geographical location of the user equipment and thus the user thereof. A mobile user equipment and the user thereof can be positioned by various different techniques. For example, substantially accurate geographical location information that associates with a user equipment can be obtained based on the known satellite based GPS (Global Positioning System). In another approach the cells or similar geographically limited radio access entities and associated controllers of the communication system are utilised in production of an estimate concerning the location of the mobile user equipment. The communication system may also be provided with specific location measurement units (LMUs) that provide data concerning the location of a user equipment.
It is also possible to conclude geographical location even if a mobile user equipment is located within the coverage area of a visited or “foreign” network. The visited network may be made capable of transmitting the location of the mobile user equipment back to the home network, e.g. to support services that are based on location information or for the purposes of routing and charging.
The production of data for the location determinations (such as various measurements and calculations) does not form an essential element of the present invention, and is thus not described in any greater detail herein. It is sufficient to note that a location service (LCS) entity may be employed in the provisioning of location information associated with a target mobile user equipment for an entity that has requested for such information (the client). The client may comprise a service application that may use the information is provisioning of location sensitive information for the subscribers to its services. The location service entity may implemented within the cellular system or connected thereto. The location service entity provided by the communication system may serve different clients via an appropriate interface. The location service entities may provide the location information based on data that has been provided by various sources. Location data may also be processed in the user equipment that is provided with appropriate processing capacity. The user equipment may then provide the location service entity or the client with, location data, for example location co-ordinates.
The client may make use of that location information for various services/applications, such as for location of a mobile telephone that has made an emergency call, for locating vehicles or given mobile subscribers for commercial purposes and so on. In general, a client such as a user or entity wishing to receive location information regarding another user may send a request for such information to the location service provision entity. The location service provisioning entity will then process the request, obtain the required data for generating a response and generate an appropriate response.
An example of the provision of the location information by a PLMN is described in more detail 3rd Generation Partnership Project (3GPP) technical specifications, see e.g. 3GPP TS 23.271 version 4.2.0, titled “Functional stage 2 description of LCS”, June 2001. According to the 3GPP specification a location service (LCS) server entity referred to as a Gateway Mobile Location Center (GMLC) is provided for managing the location services. The GMLC is for gathering and storing various data that may be used in provision of location information for the location service clients (LCS clients).
The proposed location service (LCS) solutions employ control plane signalling channels for signalling messages that associate with the provisioning of the location services, such as for requests for location information, messages for conveying location service assistance data and so on. However, the inventors have found that the signalling of messages that associate with the provisioning of the location information may cause relatively high load on the control plane. This may be especially the case on the air interface between the mobile user equipment and the radio network apparatus servicing the mobile user equipment.
The inventors have found that this problem could be overcome if the user plane could be used for such purposes. By means of this it could be possible to avoid the use of the substantially heavy SS7 (signalling system No 7) based control plane signalling. Furthermore, use of the user plane could help in solving the problem that relates to the substantially high variations in the signalling load occurring is response to the location information service enquiries or other similar unpredictably occurring service request. This is so since no resource allocation is required for the packet switched user plane communication in the manner as is required for signalling the same information over the control plane.
A specific example of user plane communication that could be used for communication of data to and from the mobile user equipment is based on the Internet Protocol (IP). However, in order to be able to transmit e.g. assistance data on the user plane in an Internet Protocol (IP) based positioning system the entity of the location service need to be made aware of the IP address of the target user equipment. A problem in this is that the IP address of the target user equipment is not necessarily known by an application making the request to the location service. Even if the IP address of the requester of the location information is known by the application making the request, and is e.g. delivered in the http-header of the request (hypertext transport protocol header) to the location information service, the target user equipment may be different from the requester accessing the application. Furthermore, the addressing schemes such as the IP addressing may vary in different domains. Thus the application, requestor, operator and the target user equipment may have different addressing scheme in use in their own domains.
The prior art does not offer a solution wherein it could be possible to establish a user plane IP connection in the event that the user plane IP address of the target user equipment is not given by the requester. However, the target user equipment may already have a user plane session and thus a user plane IP address. The possible IP address of the target user equipment is known only by an access node such as an access server (e.g. a GGSN) to which the target user equipment is connected to for the Internet Protocol (IP) user plane session between the user equipment and the IP network.
The inventors have found a need for a solution wherein an existing user plane address, such as an Internet Protocol (IP) address, can be used for communication of data to the user equipment should such as address exist.